Differential pressure responsive means



DIFFERENTIAL PRESSURE RESPONSIVE MEANS Filed Oct. 3, 1946 2 Shets-Sheet 1 Jan. 3, 3950 H. ZIEBOLZ 2 493 1 DIFFERENTIAL PRESSURE RESPONSIVE MEANS Filed Oct. 3, 1946 2 Sheets-Sheet 2 nvmvrm Tberi 2156509,

Patented Jan. 3, i950 Herbert Zicbols, Chicago, 111., minor to Regulator Company,

tion of Illinois Application October 3, 1946, Serial No. 700,887

' 9 Claims. (01. 137-151) The invention relates generally to dillerential pressure responsive'means and, more particularly, to such means adapted for use where high static pressures are present.

Where high static pressures are present, a conventional seal or packing of the stufling box type Chicag o, 111., a corpora means tor readily varying the respective lever for the rod or stem transmitting the movement oi the diaphragmof the pressure responsive means to the outside of the casing thereof is not capable of containing these highpressures and it becomes necessary to employ a positive-seal,

flexible-wall type means such as a bellows. Em-

ploying a single bellows subjected to the pressure on one side of the diaphragm, of course,

introduces an additional force acting on the .rod,-

due to the static rather than to the difierential pressure. This hasin thepast been attempted to be overcome by the employment of a second bellows mounted on the same axis with the first and acting in opposition to the first, these bellows. being normally disposed on opposite sides of the diaphragm of the pressure responsive means. The difficulty with this attempted solution, however, is the fact that it is substantially impossible to have two bellows of precisely the same area. Thus with different pressure areas there is still an unbalanced force, due to the static pressure rather than to thedifferential pressure, and where the static pressure varies through a considerable range the error thus introduced is very material and also variable.

It is an object of this invention, therefore, to

' provide a new and improved difierential pressure responsive means having positive-seal, flexiblewall type means for sealing the same for use with high static pressures, in which the effect of such static pressure on the sealing means is substantially completely eliminated despite wide varia tions in the static pressure. Another object is ,to provide differential pressure responsiveimeans having a positive, flexible wall seal for thediaphragm movement transmitting rod, in which the effect of static pressure on the seal is oil'set by another pressure responsive means associated with the seal in such nianner that diflerences in pressure areas between the two may readily be compensated for.

A further object is to provide a difl'erential pressure responsive means, with a bellows seal for the diaphragm movement transmitting rod, having a second such bellows subjected to static pressure only, a lever intended to reflect move ments of the rod caused only by deflection of the diaphragm under difierential pressures, the bellows acting in opposition on the lever, and

arms at which the bellows act to facilitate balancing of the forces created by static pressure.

Other objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a diametrical sectional view of a differentiahpressure responsive means embodying the features of this invention.

Fig. 2 is a sectional view taken 'approximately along the line 2-2 of Fig. 1 showing a portion of the difierential pressure responsive means.

Fig. 3 is a transverse sectional view taken approximately along the line 3-3 of Fig. 2.

Fig. 4 is a view similar to Fig. 3 but taken along the line 4-4 of Fig. 2.

1 Fig. 5 is a view similar to Fig. 3 but taken along the line 5-5 of Fig. 2.

Fig. dis a fragmentary viewtaken along the line 64 of Fig. 2.

While the invention is susceptible of various modifications and alternative constructions, it is shown in the drawings and will hereinafter be described in a preferred embodiment. It is not intended, however, that the invention is to be limited thereby to' the specific construction dlsclosed. on the contrary, it is intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention as defined in the appended claims.

In the exemplary embodiment herein disclosed, the invention comprises generally means ll responsive to diflerential pressures, means ll forming a positive seal for the passage of the 1 the differential pressure responsive means it is oi the diaphragm type and thus comprises a housing having a main part I i and a complementary part It, the two parts being adapted to be securely and tightly assembled by means of a plurality of bolts ll. The main part I! has at the center thereof a cup-like, axial extension l8 projecting in a direction awayfrom the closure part It, that is, downwardly, as viewed in Fig. 1. On its inner face the main part I 5 is formed with an annular, slightly depressed surface IQ for the reception of the periphery of a flexible diaphragm 2|. The diaphragm is tightly clamped onto the main part i5.- Formed in the main part I to open to one side of the diaphragm 23 is a threaded port 23, and formed in the complementary part i5 to open to the opposite side of the diaphragm is a similar threaded port 24.

It will be understood that the ports 23 and 24 will have connected thereto conduits or other means for conducting to the means Ill the differential pressure which is to be measured or responded to. I I

Movement of the diaphragm 23 is transmitted to the lever l3 through the medium of a rod 21 which terminates at the lever end in a tapered 4 and the inner end of the nipple 45. The rod 44 again terminates in a tapered bearing tip 43 similar to the tip 23. v

The lever I3 is mounted within the lowermost, as viewed in Fig. l, of three frame sections 33, II and 52 secured in suitable manner to one another and also dependingly secured to the main bearing tip adjustable to a limited degree longitudinally of the rod. At its opposite end, the

upper end as viewed in Fig. 1, the rod 21 is ad- Justably attached to the center of the diaphragm 23. The adjustable attachment of the rod to the diaphragm includes a screw 23, a nut 33 and a cap 3i having an interior cylindrical portion 32 in which the rod 21 is received with a snug lit. The rod 21 to extend outwardly of the cup-like portion 13 of the main part l5 must pass through part II or the ditl'erential pressure means II. The lever comprises airlock 53 from which depends an extension 54 rigid therewith andcarrying at its free end an adjustable bolt 55 formed with an axial socket 53 for the reception of the bearing end of one element of a linkage system. The lever I 3 is adapted to pivot in the plane of Fig. 1 and is herein given a unique mounting in order that both the pressure differential means II, the positive seal II and the static pressure compensating means I 2 may, through their respective rods 21 and 44, act thereon to result in pivoting of the lever in accordance with variations in the differential pressure only. To that end, the block 53 is rockably supported through the medium of an element 51 giving knife-edge support. The element 51 has a cylindrical, interthe end wall 33 of the cup-shaped portion. To I that end, the end wall 33 is provided with an opening 34 in which is received an elongated nipple 35 having a bore 35 therein which is largirthan the rod 21 so as to permit free axial movement of the rod through the nipple. At itsinner end, the hole 34 is beveled to form an outwardly flaring, frusto-conical surface 31. The inner end of the sleeve is enlarged to form a head 33 and this head is formed with a radius 39 adapted to engage the frusto-conical surface to form a seal eifective to withstand high pressures. The outer end of the nipple is threaded to receive a nut 43 for drawing the radius of the head very tightly against the frusto-conical surface 31.

As already stated, a positive sealing means H is provided for the passage of the rod through the housing of the pressure responsive means. This positive seal herein takes the form of a flexible-wall means, more particularly, a bellows 4|. One end of the bellows is securely clamped in the cap 3i while the other end is securely clamped in It is clearly apparent to those skilled in the art that the bellows 4| is subject to and responsive to the static pressure in the chamber within the cup-shaped portion l3. Thus, the effect on the rod 21 is the combined effect of the difl'erential pressure acting on the diaphragm 20 and the static pressure acting on the bellows 4|, and movement of the rod 21 does not represent the static pressure differential. The means I2 is provided herein for oiisetting or counteracting this effect of static pressure on the bellows 4|. To that end, there is provided in the same chamber with the bellows 4| a second bellows 42 which is selected to be as nearly identical with the bellows 4| ,as possible. Like the bellows 4|, the bellows 42 has a can 3, at one end which is snugly mounted upon one end of a second rod 44 extending parallel but in slightly spaced relation to the rod 21. The rod 44 passes freely through a second nipple'45 identical with the nipple 35, with the bellows 42 secured at its ends in the cap 43 mediate portion and is rotatably received in a bore 33 formed in the block 53 and extending at right angles to a plane through the rods 21 and 44. The ends of the element 51 project beyond the block 53 and have a sector-like transverse cross section with the apex of the sector-like ends lying in the circumference of the element.

The element 51 is cradled in a bracket 53 (see Figs. 1 and 2) projecting from one wall of the section 52 and having a pair of braces 53 and 3|. Joining the braces are cross members 32 each carrying a hardened insert 53.- Each insert 33 is slightly recessed in its top surface to receive the apex edge of the sector-like ends of the element 51. Formed in the block 53 to either side of the bore 58 are a pair of tapering sockets 54 for the reception of the bearing tips 28 and 45. At the bottom of each socket 54 there is preferably positioned a small hardened insert 55 having a conical recess in the exposed surface for cooperation with the bearing tips 23 and 45.

While the sockets 54 are fixed relative to the bore 53, means is herein provided which in eflect changes the respective movement arm at which the rods 21 and act on the block '53 and thus changes the effect which the bellows 4i or 42 have on the lever. This is herein accomplished by rotary adjustment of, the element 51 within the bore in the block 53. To that end, the block has formed therein a passage, herein a channel 55 extending transversely of the bore 58 and intersecting the bore. Disposed within this channel is a pin 51 extending transversely through and having a. tight flt within the element 51. The pin 51 has a diameter smaller than the dimension of the channel in the plane transverse to the bore 53 and the element 51 in order that the pin 31 may have limited pivoting movement, that is, rotational movement of the element 51. In order to efiect the required adjustments of the element 51 a pair of set screws 58 is provided. These are threaded in the block 53 and project into the channel 33 for engagement with the pin 81 near the ends thereof. Intermediate the-screws 83 the block 53 carries a third set screw 69 which projects into the bore 53 for engagement with the element 51 to aid in locking the element in adjusted position.

It is believed readily apparent from the foregoing that the bellows 4| and 42 can, through the medium of the moment arm adjustin means just described becaused to have the same eflect on the lever l3 and that. as a result, the elect oi static pressure on' the bellows II can be com- I pletely and eflectively counteracted and onset by the bellows 42 so that the movement imparted to the lever It will be truly and only that produced .by the diflerential pressures. This is true not only for one value 01' static pressure but is also true over a wide variation of the static pressure to which the bellows are subjected. As above pointed out, the, invention herein disclosed is believed to be the first solution to the problem of providing a diflerential pressure responsive means subjected to high static pressures which assures a complete balancing or oilsetting or the static pressure over a wide range or static pressures. With all the construction is.rugged, simple and should require very little in the way oi maintenance or readjustment once'properly ad.- justed to eliminate the effect of static pressures.

I claim as my invention:

l. A diflerential pressure responsive device comprising a housing, a "flexible diaphragm mounted within said housing dividing the same into two pressure chambers, a rod secured at one end to said diaphragm and projecting at the other end outwardly of said housing, a flexiblewall means for positively sealing the passage of said rod through said housing secured at one end to said housing in surrounding relation to the passage for the rod and at the other end to said rod, a lever mounted to be actuated by said rod in response to differential pressures acting on said diaphragm, means responsive to static pressure" and subjected to the same static pressure as said sealing means acting in opposition to the tendency or; the static pressure acting on said sealing means to rotate said lever, and means for equalizing the effects of said sealing means and said last named means on said lever to eliminate the efiect of 'static pressure on said sealing means.

' 2. A diilerential pressure responsive device comprising a housing, a flexible diaphragm mounted within said housing dividing the same into two pressure chambers, a rod secured at one end to said diaphragm and projecting at the other end outwardly of said housing, flexiblewall means for positively sealing the passage of said rod through said housing secured at one erid to said housing in surrounding relation to the passage for the rod and at the other end to said rod, a lever mounted to be actuated by said ango first named bellowsfand means for'adiusting" the {noment arms atwhich said bellows act on said ever.

4. A- (inferential-pressure responsive device comprising a, housing, a flexible diaphragm mounted within said housing dividing the same into two pressure chambers, a rodsecured at one end to said diaphragm and projecting at the other end outwardly oi. said housing, a bellows secured at one end to said rod and at the other end to said housing in surrounding relation to said rod to seal the passage 01' said rod through said housing, a lever, a pivot for said lever, said rod engaging said leverto one side of said pivot,-a second bellows disposed in the same chamber as said first named bellows, a rod actuated by said second bellows engaging said lever on the side of its pivot opposite said first named rod, and means for adjusting the pivot of said lever to adjust the relative length of the moment arms at which said rods act on said lever.

rod in response to difierential pressures acting on said diaphragm, means responsive to static presinto two pressure chambers, a rod secured at one end to said diaphragm and projecting at the other end outwardly of said housing, a bellows secured at one end to said rod and at the other end to said housing in surrounding relation to said rod within one chamber to seal the passage of said rod through said housing, a lever mounted to be actuated by said rod in response to diiierential pressures acting on said diaphragm, a second bellows exposed to the pressure in said one'chamber only and acting on said lever in opposition to said 5. A differential pressure responsive device comprising a housing, a flexible diaphagm mounted within said housing dividing the same into two pressure chambers, a rod secured at one end to said diaphragm and projecting at the other end outwardly of said housing, a bellows secured at one end to said rod and at the other end*to said housing in surroundin relation to said rod to seal the passage of said rod through said housing, a second bellows disposed in the same chamber as'said first named bellows, a rod actuated by said second bellows extending outwardly of the chamber parallel with said first named rod, a

lever having a bore therethroughtransversely of 6.A differential pressure responsive device comprising a housing, a flexible diaphragm mounted within said housing dividing the same into two pressure chambers, a rod secured at one end to said diaphragm and projecting at the other end outwardly of said housing, a. bellows secured at one end to said rod and at the other end to said housing in surrounding relation to said rod to seal the passage of said rod through said housing, a second bellows disposed in the same chamber as said first named bellows, a rod actuated by said second bellows extending outwardly of the chamber parallel with said first named rod, a lever having a-bore therethrough transversely of the plane in which the lever is to swing, a pivot for said lever comprising an element having a rotatable fit in the bore and extending to both sides of said lever, the ends of said element having a sector-like transverse cross section, a cradle for rockably receivin the apex edge of the ends of said element for supporting said lever in position comprising a, housing, a flexible diaphragm mounted within said housing dividing the same into two pressure chambers, a rod secured at one end to said diaphragm and projecting at the other end outwardly of said housing, a bellows secured at one end to said rod and at the other end to said housing in surrounding relation to said rod to seal the passage 01' said rod through said housing, a second bellows disposed in the same chamber as said first named bellows, a rod actuated by said second bellows extending outwardly of the chamber parallel with said first named rod, a lever having a bore therethrough transversely oi the plane in which the lever is to swing, a pivot for said lever comprising an element having a rotatable lit in the bore and extending to both sides oi said lever, the ends of said element having a, sector-like transverse cross section, a cradle for rockably receiving the apex edge of the ends of said element for supporting said ever in position' to be engaged by said rods one on each side of the bore, and adjustable, means ior determining the angular position or end outwardly of said housing, a bellows secured.

at one end to said rod and at the other end to 'said housing in surrounding relation to said rod to seal the passage of said rod through said housing, a second bellows disposed in the same chamber as said first named bellows, a rod actuated by said second bellows extending outwardly of the chamber parallel with said first named rod, 9.

leverhaving a bore therethrough transversely of asoaiso 8 theplaneinwhichtheleveristoswinmaplvbt for said lever comprising an element having a rotatable lit in the bore and extending to both sides of said lever. the ends oi. said element having a sector-like transverse cross section, a cradle "for rockably receiving the apex edge oi the ends oi said element for supporting said lever in position to be engaged by said rods one one each side oi the bore. said lever having a passage extending at right angles to and intersecting the bore therein, a pin extending transversely through said element and along said passage, said passage being wider than said -pin to permit limited rotation at said element, and a pair 0! set screws each engagin; said pin near one end thereof.

9. A diii'erential pressurev responsive device comprising a housing, flexible means mounted within said housing dividing the same into two pressure chambers, movement transmitting means secured at one end to said'flexible means and projecting outwardly of said housing for transmitting the movement of said flexible means, flexible-wall means for positively sealing the passage of said movement transmitting means through said housing secured to said housing and to said movement transmitting means, a lever mounted to .be actuated in response to diii'erential pressures acting on said flexible means, and means responsive to static pressure subjected to the same static pressure as said flexible-wail means and connected into the device to be operable to nullify the eil'ect of static pressure on said flexible wall means.

' HERBERT ZIEI BOLZ.

No references cited.- 

